Various programs and incentives exist which dictate, to a certain degree, the manner in which blood donations occur. In some cultures where blood and/or plasma is sold, donors frequently will travel to a permanent location to effect the exchange. This procedure has certain benefits in that a normal, electrically powered, commercial refrigeration system can be used to blast freeze the drawn plasma.
It is imperative that the blood plasma be frozen as soon as possible after collection in order to maintain its highest qualities. Blood plasma proteins are thermolabile and can degrade in quality from its highest level to an inferior grade quite quickly. Thus, fixed locations with permanent blast freezing capabilities can be effectively utilized to preserve the blood in its highest quality immediately after collection.
However, there is an increasing demand for plasma from individuals that are willing to donate their plasma at no charge. In order to attract these donors, the collectors must set their equipment at sites convenient to the donors, often remote from the main blood processing centers. In some cases a mobile unit, such as a large van, will be sent to remote locations and effect plasma collection when a fixed processing site is geographically inconvenient to the donor. While such large expensive vehicles, which have the beds and processing equipment onboard, can collect the blood products, they do so at a relatively high cost per liter of plasma collected and the donor is still required to leave his place of business and go to the van to donate his blood or plasma.
More often it is required to be even more convenient for the donor - that is to set up within the donor's place of work. However these locations are often up in buildings and require the lifting and handling of all the necessary equipment by the blood collection staff. An onerous job results.
The necessary equipment to collect plasma is usually transported in smaller vans to these private or public buildings which house a suitable population of workers who are willing to donate their blood or plasma, now that the location of donation site is so convenient. In both of these methods of collecting blood or plasma the cost is quite high.
Consequently, because it is especially important that such expensive blood products be collected and maintained at their highest quality, this requires refrigeration which is compact, light weight and easily transportable by one or two people. Until now, the only means available for rapid freezing in such circumstances was from the use of very expensive, expendable cryogens like LN.sub.2 and CO.sub.2. In addition to being costly, LN.sub.2 and CO.sub.2 are somewhat dangerous to handle and are so cold they embrittle the plastic bags which house the plasma. These weakened bags often break which leads to extraordinary costly wastage of precious fluids.
Other similar examples of sites where the importance of collecting high quality blood exists include within relatively undeveloped countries that have low levels of industrialization and during military maneuvers. Both describe situations where collection is most arduous.
The following patents reflect the state of the art of which applicant is aware insofar as these prior art citations appear germane to the process at hand. However, it is stipulated that none of these patents teach singly nor render obvious when considered in any conceivable combination the nexus of the instant invention as particularly claimed and described.
______________________________________ INVENTOR PATENT NO. ISSUE DATE ______________________________________ Hjerstrand, et al. 4,145,895 March 27, 1979 Faust, et al. 4,194,369 March 25, 1980 Sheehan, et al. 4,322,954 April 6, 1982 Campbell, J. H. 4,343,158 August 10, 1982 Morris, S. D. 4,470,264 September 11, 1984 Toledo-Pereyra, L. 4,502,295 March 5, 1985 Van Iperen, et al. 4,923,077 May 8, 1990 ______________________________________
The patent to Morris teaches the use of a life support apparatus for human blood and compositions thereof in which a transportable self-contained life support apparatus steadily reduces in temperature whole blood collected from donors to a predetermined temperature range which is above freezing because whole blood cannot be frozen without damaging the cells. Unlike the instant invention, no freezing is involved and as will be developed infra, no eutectic mixture is integrated into the Morris apparatus. As a result, the blood stored according to this known prior art technique is at a higher temperature than that which is attainable in the instant invention and which is much more desirable.
Similarly, the patent to Hjerstrand, et al. teaches the use of an apparatus for storing goods at stable temperatures in a heat-insulated container in which the resident ideal temperature results in a temperature which is greater than that of the freezing temperature of water. Therefore, the blood plasma to be stored in such a device would be held at a temperature which is elevated compared to the instant invention.
The patent to Faust, et al. teaches the use of a cryogenically frozen package article in which two plates are adapted to rotate about a common line of registry so that a pouch containing blood plasma is sandwiched therebetween. There is no integral cryogenic liquid associated therewith, and therefore does not provide an eutectic liquid as does applicant for the beneficial remote cooling according to the instant invention.
The remaining citations show the state of the art further and diverge even more from the claimed inventive nexus as described infra.